<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .container {
      display: flex;
      width: 100%;
      height: 100vh;
    }

    .left, .right {
      padding: 20px;
      flex-shrink: 0;
    }

    .left{
      width: 200px;
      background-color: lightblue;
    }

    .center {
      background-color: lightgreen;
      flex-grow: 1;
    }

    .right{
      background-color: lightcoral;
      width: 200px;
    }
  </style>
</head>
<body>
  <div class="container">
    <div class="left"></div>
    <div class="center"></div>
    <div class="right"></div>
  </div>
</body>
</html>